Band 2 (apparent mol wt approximate 220,000) of the human red cell membrane is a major substrate for endogenous protein phosphorylation and accepts the transfer of 32P from (gamma-32P)ATP to a greater extent in membranes from patients with Duchenne muscular dystrophy (DMD). Our laboratory is engaged in structural comparisons of DMD and control Band 2 using the 32P-labelling as an indicator for a potential structural abnormality. Tryptic peptide analyses using high pressure ion exchange liquid chromatography and other analytical procedures are in progress. Parallel experiments designed to isolate the major 32P-phosphorylated cyanogen bromide cleavage products are also in progress. To date several differences are and have been observed in DMD and experiments are in progress to determine whether the differences are disease specific or polymorphisms of the large Band 2 molecule. Genetic studies within pedigrees in which there are more than a single affected male are planned to attempt the necessary correlation between particular peptide patterns and patients and carriers in a single pedigree.